The invention relates to a method for the production of liquid products, particularly, tar, from organic bulk materials. The method is intended for an apparatus having one or a multitude of refining stages in the coal processing or related industry.
Methods for the prior production of tar are known, whereby coke and gas are produced as by-products. The publication DD-PS No. 48389, for instance, refers to a two-stage method for the short-interval low temperature carbonization of unbriquetted, solid fuels high in inerts, with an apparatus which essentially comprises a dryer and a low temperature carbonization aggregate, and whereby in both apparatus an individual homogeneous fluidized bed is built up over an influx floor. The fluidized beds receive their heat supply, whereby low temperature carbonization gas is carbonized to flue gas in a carbonization chamber, whereby to the fluidizing medium for the dryer is added a part of the vapors of the dryer, and to the fluidizing medium for the carbonization aggregate is added cold low temperature carbonization gas. On the side of the gas, between the dryer and the low temperature carbonization aggregate, is provided a filter which removes the dust from the mixture of vapors and flue gas transported out of the dryer. The removed dust is added via an immersion pipe slightly above the influx floor to the fluidized bed of the low temperature carbonization aggregate.
A modified method, intended for increasing the yield of light liquid products, provides for the injection of heavier hydrocarbons, such as, for instance, residual oils, asphalts, and the like, into the fluidized bed of the low temperature carbonization aggregate.
A further characteristic of the invention consists in transferring the low temperature carbonization gas recovered from the low temperature carbonization aggregate selectively either to a filter or to a cracking apparatus, in order to perform a cracking of the tar vapors and to remove coke dust.
Subsequently thereof, the low temperature carbonization gas is cooled in a waste heat boiler and transferred to a condensation and benzene removal chamber. The low temperature carbonization gas treated in this way is utilized as heating and/or as rinsing gas. The low temperature carbonization gas produced in the cracking apparatus differs from the low temperature carbonization gas produced in the conventional way, insofar, that the tar yield is reduced in favor of lighter products and gas.
The disadvantages of the described method are that charging the dust from the filter into the fluidized bed of the low temperature carbonization aggregate leads to an enrichment of the dust content of the tar vapors forming therein, whereby an unfavorable ratio develops between the heavy tar low in dust and the tar containing dust. Furthermore, it also increases the cost of auxiliary agents, because in accordance with the method, heavier hydrocarbons are injected into the fluidized bed for the purpose of increasing the tar yield.
Furthermore, in a separate stage of the method, there exists the possibility of cracking the tar vapors, and increasing the portion of the components which boil easier. The refining of the low temperature carbonization gas thereby occurs subsequently in various reaction chambers, so that the cost of the apparatus and the system engineering is comparatively high.
In addition, a method for the rapid pyrolysis of lignite in the fluidized bed (WP C 10 B/2490798) has been proposed. It has the objective of producing the three main products, coke, gas, and tar of high quality and high yield.
The method works in two stages with a dryer and a pyrolysis reactor, whereby in each of the two apparatus a fluidized bed is built up over an influx floor. The heat supply to the fluidized beds building up in the dryer occurs by a specific mixed gas (WP F 23 C/2530430), and in the pyrolysis reactor, firstly, directly via the heated fluidizing medium and, secondly, indirectly via a nest of boiler heat transfer pipes.
As a fluidizing medium for the pyrolysis reactor, a low temperature carbonization gas alien to the pyrolysis has been proposed. A special feature of the invention is that the dust from the dryer is not transferred into the pyrolysis reactor, but is removed from the actual work cycle of the method, and is utilized in by-processes. This is meant to shift the equilibrium in the tar formation phase in favor of the tar low in dust, which is especially suitable for electrode coke production.